When a thermoplastic resin or a thermosetting resin is blended with inorganic fillers such as glass fibers, silica, talc, and the like, the resin may have improved tearing strength, tensile strength, flexural strength, flexural modulus, and the like due to the inherent properties of the inorganic filler. Blending of a thermoplastic resin such as polycarbonate and the like with inorganic fillers is usually performed in a process of preparing a molded article requiring high rigidity. Particularly, the blend can be used as an interior/exterior material for automobiles as well as electric and electronic products.
However, when the resin is blended with inorganic fillers, the resin may have problems during injection molding due to reduced moldability. Specifically, when the resin is injection molded, there is a possibility that inorganic fillers such as glass fibers and the like may protrude from the surface of a molded article, which leads to deterioration in appearance. Thus, the resin is limited to use for production of indoor articles in practice.
Further, when flowability of a thermoplastic resin composition blended with inorganic fillers such as glass fibers and the like is improved, appearance may be enhanced, but there are problems in that mechanical and thermal properties of the resin composition can decrease with the increase of flowability.
Korean Patent Publication No. 10-2012-0075813A discloses a glass fiber-reinforced polycarbonate resin composition including a glass fiber-reinforced polycarbonate resin, a metal salt flame retardant, a fluorinated polyolefin resin, and a mixture of a siloxane compound and a silicone resin composition, and having excellent flame retardancy. Further, Korean Patent Publication No. 10-2012-0057276A discloses a glass fiber-reinforced polycarbonate resin composition having enhanced color stability at high temperatures. These resin compositions can enhance rigidity and flame retardancy through glass fiber reinforcement. However, these resins are poorly suited for exterior is applications due to rapid deterioration in appearance over time.
In order to enhance appearance, injection molding such as rapid heat cycle molding (RECK) and the like may be used. However, this method requires an expensive injection machine and a long molding cycle period, which can reduce productivity.